Call-distributing system.



H. P. CLAUSEN. 4 'CALL DISTRIBUTING SYSTEM. APPLICATION FILED OCT. 1. 1915.

1 ,1 92,1 65 Patented July 25, 1916.

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H. P. CLAUSEN.

CALL DISTRIBUTING SYSTEM.

APPLICATION FILED OCT. 1. 1915.

'1 ,1 92, 1 65, Patented July 25, 1916.

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CALL DISTRIBUTING 'SYSTEM.

APPLICATION FILED OCT. I. 1915.

Patented July 25, 1916.

4 SHEETS-SHEET '3 H. P. CLAUSEN.

CALL DISTRIBUTING SYSTEM.

APPLICATION FILED OCT-1,1915.

Patented July 25, 1916.

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UNITED STATES PATENT OFFICE.

HENRY P. CLAUSEN, OF MOUNT VERNON, NEW YORK, ASSIGNOR, BY MESIIE ASSIGN- MENTS, TO \VESTERN ELECTRIC COMPANY, INCORPORATED, A CORPORATION OF NEW YORK.

CALL-DISTRIBUTILZG SYSTEIYL Patented July 25, .1916.

Application filed October 1, 1915. Serial No. 53,585.

To (125 whom it may concern: 4

Be it known that I, I'IENRY P. CLAUSEN; a citizen of the United States, residing at Mount Vernon, in the county of \Vestchester and State of New York, have invented certain new and useful Improvements in Call- Distributing Systems, of which the following is a full, clear, concise, and exact description.

This invention relates to call distributing systems. In systems of this class the incoming telephone calls are automatically distributed before idle trunk operators, so that the work of the various operators is equalized, and so that the subscribers calls will receive prompt attention.

The object of this invention is to com bine a call distributing system with a telephone system in which the incoming lines are associated with automatic switching means which select idle trunks, whereby the traffic passing over the busy trunks is elliciently distributed to idle connecting links in front of idle operators.

It has been demonstrated in practice that during the normal busy hours 86% of the traffic will be carried over the first four trunk circuits of an automatic switch which has access to ten trunk lines. The telephone traliic carried by the various trunks of such a switch will be divided in substantially the following ratios: The first trunk will carry a maximum of 32% of the trafiic; the second trunk, 24%; the third trunk, 18%; the fourth trunk, 12%,; the fifth trunk, 7%; the sixth trunk, 3%; and the seventh trunk, 2%, and the remaining three-trunks will divide the remaining 2%. Summing up the foregoing figures, it will be observed that the first trunk carries 32% of the traffic; trunks 1 and 2, 56%; trunks 1, 2 and 3, 74%; trunks 1 to 4 inclusive, 86%, etc.

In accordance with this invention the first few busy trunk lines, for example the first four, which carry substantially 86% of the total traffic, are connected to automatic distributing switches while the remaining trunk lines terminate direct in idle connecting links, and for {his reason all the telephone trafiic of the exchange will be auto matically distributed to. idle connecting ,links before idle operators as lon as such trafiic does not exceed 86% of the total trafiic. Whenever the trafiic exceeds 86%, provided the first four trunk circuits are will be connected over the trunk line direct to idle connecting links. Switches for automatically distributing incoming calls according to this invention, will consequently have to be provided for but a small percentage of all the switches directly associated with the incoming lines, and at the same time practically all the inherent advantages of a full call distributing system will be maintained. Therefore the advan tages of this system reside in the rendering of more efficient service and in the economy of installation. Other advantages of the invention will be pointed out in the following description and the appended claims.

The invention is illustrated in the accompanying drawings in which all the apparatus is shown in its normal or unactuated condition.

Figure 1 illustrates a subscribers line circuit and the circuits of an associated finder switch. Fig. 2 shows the distribnter switch and an operators connecting cord circuit. Fig. 3 illustrates a preferred method of grouping the incoming lines and finder switches in connection with the distributing switches and the incoming circuits. Fig. 4 shows an alternate method in which the distributing switches are associated with trunks terminating in line switches, said latter switches being connected to the incoming subscribers lines.

In the preferred embodiment of the invention shown in Fig. 3, the incoming lines are associated with the finder switches 5, 6, 7 and 8 of the first group of say 100 lines, and finder switches 9, 10, 11 and 12 with the last group of 100 subscribers lines. Each of these finder switches serve a group of 100 subscribers lines and in service Ordinarily ten of such switches would be provided for each 100 line group, and as many of these groups would be provided as would be. necessary to serve all subscribers in the telephone system.

The finder and distributing switches used in the description of this invention are of the two-movement around-and-up type and are well known to any one skilled in the art. As shown in the illustration, Fig. 3, the first two finder switches 5 and 6 of the first group. and S) and 10 of the last group are associated with distributing switches 15 and 16 of the first group and 17 and 18 of the last group respectively. Manifestly the number of these distributing switches which should be provided will depend upon the percentage of the telephone traflic which is to be distributed,

A further description of the grouping as illustrated in Fig. 3 will be deferred until a description of thecircuits illustrated in Figs. 1 and 2 has been completed, when the grouping as shown in Fig. 3 will be more readily comprehended. I

Referring now to Fig. 1, when the subscriber removes his receiver from the hook he will cause the operation of the line relay 20. The operation of this relay will complete a circuit from battery through the alternate contact and armature of this relay.

to the coil of relay 21 and thence through the normal contact and armature ofi'elay 23 to. ground, thereby energizing relay 21. The operation of the left-hand armature of relay 21 will complete a locking circuit for this relay from ground through its lefthand armature, the coil of relay 21 and the armature, alternate contact, andcoil of line 'relay 20 to battery. The attraction of the right-hand armature of relay 21 will complete a circuit from ground through the coil of relay 23 to battery. Relays 21 and 23 are common to a group of 100 lines and are multiply connected to the left-hand arma ture of the line relay 20 as shown in the circuit diagram, Fig. 1. The operation of rclay 23 opens the initial energizing circuitof relay 21 at its left-hand armature, and at its right-hand armature completes a circuit which can be traced from the ground on the right-hand armature of relay 21, through the right-hand armature of relay 23, side switcharm 26, the armatures of the release magnet 2.7,the brush magnet 28, and

the vertical magnet 29, side switch arm 30, and the coil of the brush step magnet 28 to battery. The completion of this circuit will operate the brush magnet, and as this circuit is self-interrupted, at the armature of the brush magnet, said magnet will be repeatedly energized, thereby moving the brush arm 32 stepiby step until this brush rests on a contact34 associated with the group of contacts in which the'terminals' of the calling line are located. These brush con-- The group test relay 36 is common to agroup of ten lines. When the group brush 32 is switched tothe contact 34, associated with a group in which a line is calling, a

circuit is completed from the ground on' the armature of relay 36, to contact 34, and thence by way of-brush 32 and the-side switch arm' 37 and escapei'nent magnet 38 to battery. This causes the energization of the escapement magnet which thereby moves side switch arms 26, 30, 37, 39 and 40 into their second position.

In' the second position of the side switch a circuit is closed for the vertical magnet 29 from battery through said .magnet, the side switch arm 30, the armature of the'vcrtical magnet 29, the armatures of the brush magnet 28 and the release magnet 27, the side switch arm 26, and the right-hand armatures of relays 23 and 21', to ground. This will cause the energization of the vertical magnet 29, which'in operating interrupts its own circuit, and thus moves the brushes 42, 43 and 44 of the finder switch step bystep 'over the contacts of the group selected, until the terminals of the calling subscribers line are found. When the contact wipers of the finderv switch rest on the terminals of the calling line, a circuit is completed from ground through the resistance coil 45, the test contact wiper 42, and the cut-off relay 47 to battery. The subsequent energization of the cut-off relay 47 will open the circuit of the line relay 20, and this in turn will cause the deenergization of the group starting relays 21 and 23. The deenergization of the roupstarting relays removes the ground rom the circuit which contained the escapement magnet 38 in its operated posi switch arm 26 to the next idle finder switch.

Since the calling subscribers line has .now been extended to the distributer switch, the line relay 50-will be'energized. The operation of this relay closed a circuit from the ground on its'armature and theoff-normal contact '56, to the side switch arm 51, and thence by way of the normal' contact, the

armature and coil of the brush magnet-52, 3

to battery. The energizing circuit of the escapemcnt magnet 53 will likewise be i closed, since it is contained in a parallel circuit with'the brush magnet b way of the side switch arm 54. Thecomp etion of'the energizing circuit of the brush magnet 52 will cause this magnet to move the brush 55 over the group contacts step by step until an idle operators position has been found. Whenever an operators position is busy, the

group contacts 58.will be grounded, and consequently the es'capemen t magnet 53 will be held in its energized position until a contact is reached from which the ground has been removed.

When the brush arm 55 finds a magnet 53 will be energized, and the side switch arms59, 60, 54, 51, 61 and 62 move into their second position.

In the second position of the side switch, the circuit of the vertical magnet 75 is closed, which circuit may be traced from battery through the coil and armature of the magnet and the side switch arm 61 to ground. The vertical magnet75 will consequently stop the contact wipers 64, 65 and 66 of the distributer switch over the switch cord contacts of the operators position selected, until the terminals of an idle cord circuit are found. When the terminals of an idle cord circuit are found, a circuit will be completed from battery through the escapement magnet 53, the side switch arm 54, the contact wiper 66, right-hand armature 1, and normal contact of relay 68 and the normal contact and right'hand armature of relay 69 to groun The subsequent operation of the escapement magnet 53 will move the side switch arms of the distributer switch into their third position. This movement of the'side switch arm 61 from the second to the third position will permanently inter-- ture to armature 1., of relay 76, and the coil of relay 77 to battery. A circuit will like wise be closed from ground through the lefthand armature of relay 68, armature 2 of relay 76, alternate contact and spring 78 of the operators telephone jack, to the group contact 58. This will render this operators position busy. 1

The operation of relay'l- 7 will connect the operators telephone circuit to the ofiice trunk connected to the calling subscriber by means of a path which may be traced from the tip side of the trunk by way of contact 70 through the left-hand armature of relay 77, the tip springs and the telephone re ceiver of the operators telephone circuit, the secondary of the induction coil, and the right-hand armature of relay 77 to contact 71 and the ring side of the trunk. The oporator is-now in a condition to converse with the calling subscriber and will ascertain the number of the line desired.

W' hen the number of the desired subscriber has been determined, the operator will insert the selected cord into the jack of the desired subscribers line. The cord selected will be indicated to the operator by the,

illumination of lamp 72. The circuit for this lamp may be traced from battery through the lamp and then by way of the left-hand armature and alternate contact of relay 69, the normal contact and armature 1 of relay 76, and the left-hand armature and alternate contact of relay 68 to ground. When the operator plugs into the jack a circuit is completed from battery through the coil of relay 80, the sleeve of the jack and plug, andthe coil of the relay 76, to ground.

The subsequent energization of relay 76 will open the circuit of the listening relay 77 and disconnect the operators talking circuit from the trunk line. At the same time a circuit will be completedfrom the ringing generator through the ringing relay 81, alternate contact and armature 2 of relay 68, alternate contact and armature 3 of relay 76, and thence to the ring of the cord and jack out on the line of the desired subscriber, returning by way of the tip of the line and the tip of the jack and plug and armature 4 of relay 76, to ground. This will signal the desired subscriber who in answering will re.

duce the resistance of the subscribers loop circuit sufliciently to energize the ringing relay'81. The operation of the ringing relay 81 will open a circuit normally shunting relay 84, and consequently this relay will be energized by a circuit which may be traced from battery throughthe coil of relay 84, resistance 85, alternate contact and armature 2 of relay 76, and left-hand armature of re lay 68 to ground. The operation of relay 84 will attractits armatures and thereby connect the calling subscriber over the cord selected to the subscriber desired.

When the subscribers have completed their conversation and hang up their receivers, the battery supply relays 69 and 90 will be deenergized. The retraction of the armature of relay 90 will close a circuit which may be traced from battery by way of lamp 73 and the armature and normal contact of said relay to the alternate contact and armature 2 of relay 76 and the left-hand armature of relay 68 to ground. This will light the calling supervisory lamp 73 and indicate to the operator that. the called subscriber has hung up the receiver. The retraction of the lefthand armature of relay 6.) will close a circuit from battery through the ans .\-'ering supervisory lamp 72, the armature and alternate contact of relay 69 and thence by way of the alternate and armature 2 of relay 76 to the left-hand armature of relay 68 and ground. This will light the answering supervisory lamp 72 and indicate to the operator that the calling subscriber has hung up the receiver. WVhen the answering and calling supervisory lamps have been lighted, the operator will know will take down the connection, thereby restoring the apparatus associated with the particular cord circuit used.

The release of the line finder and distributer switches used in setting up the connection is under the control of the line relay 69. The retraction of the right-hand armature of this relay will close a circuit which may be traccd'from the ground on the right-hand aru'iature of relay 69 byway of normal contact and armature 1 of relay 68, contact wiper of the distributer switch, side switch arm 62 and relay 91 to battery. The subse quent operation of relay 91 will close a circuit from the ground on its left-hand armature through the release magnet 27 of the finder switch, and-the release magnet 93 of the distributer switch in parallel to battery. The consequent operation of these release magnets 27 and 93 will restore the finder and distributor switch used in setting up the connections in their normal position.

For all calls that are not to be distributed the apparatus associated with the distribute! switch shown in the left-hand portion of Fig. '2, is omitted, and the trunk circuit leading from the finder switch shown in Fig. 1, is

connected direct to the cord circuits of the- A particular operators position. detaileddescription of the operation ofthis circuit is deemed unnecessary as it is identical to. that already given with the mere omission of that part of the description which refers to the operation of the dist ributerswitch.

Referring now to Fig. 3, itwill be observed that the lines are divided in groups, 'of which the first and last group are shown in the figure. These groups may be of any size, a group of subscribers lines being preferably used in practice. Whenever a call is initiated in any group, the first idle finder switch ofthe switches allotted to that particular group, will hunt for and connect with the terminals of the line called. If this finder switch happens to be one of the finders which is associated with a trunk carr ing a large percentage of the telephone tra c in that group, that is, if-it happens to be one of the first two switches as shown in Fig. 3, it-is connected tofone of the distributer switches 15 and 16 as shown in the figure. However, whenever the trafiic load is greater than that which it has been decided it will be economical to distribute, the incoming calls are trunked' from the finder switches direct to connecting cords, as illustrated by finder switches 7 and 8 of the first group, and 11 an 12 of the second group in Fig. 3. g

It will benoted that the operation of the finder switches is dependent upon the group starting relay 23, as shown in Fig. 1 and in Fig. 3. This relay 23 controls the ground which is connected to the extended starter wire circuit, and the first finder switch of 'volving this invention. switches What is claimed is:

the group, whose side switch arm is in position 1, will be operated. It is obvious that the first or busy finder switches will be operated before the starter wire will be extended to the finder switches which are not associated and connected to distributer switlches. Consequently, when the distribut ing switches are associated with finder switches and grouped in a manner substantially the same as that disclosed in the preferred embodiment of the invention shown in Fig. 3 the system will derive approximately all the inherent advantages of a fulldistributed system, even through but a small percentage of the automatic switches associated with the incoming calling circuits are connected to distributer switches.

Fig. 4 shows an alternative scheme in- In this figure 100 and 101 represent line switches which are directly connected to incomingsubscribers lines, while switches 102 and 103 represent the distributing switches. It will be noted that the trunks connected to the first two terminals of the line switch areconnected to the distributingswitches 102 and 103, which can then distribute shown wired to distributing switches in F ig.

3 as well as in Fig. 4, so that these circuits might be simplified as much as possible. Ordinarily 3 or 4 or even 5 of the trunk circuits would be associated with distributing switches so as to obtain an efiicient distribu:

tion.

As previously indicated, it will follow that if four of the trunks are associated with distributing switches 86% of the traflic coming in over the group will be distributed Whereas if five of the trunks are connected to distributing switches, 93% of the telephone trafiic will be distributed.

Obviously this invention is not limited to the specific embodiment herein shown and described, but is capable of many variations and applications without departing from its spirit and scope.

1. In a telephone system, the combination with an operators connective means controlled by a connecting operator, of automatic switching means, telephone lines extending from substations to the central OifiC and terminating in said switching means one or more of said switching means being extended directly to said connective means automatic distributing means for extending prevent the auxiliary plugs from being auto-' matically associated with one of said lines' when an unanswered call is associated with one of said connecting plugs.

3'. In a telephone system, the combination with. a plurality of lines, of selecting switches inwhich said lines terminate, op-

erators connective means directly connected to a plurality of said switches, operators auxiliary connective means associated with a plurality of operators, automatic distributing switches associated with said auxiliary connective means and with. one or more of said selecting switches, and means to automatically extend one of said lines to an auxiliary connective means when the directly coi'mected connective means of a position are id. e.

4. In a telephone system, subscribers lines divided into groups, a plurality of selecting switches for each group, connective means individual to an operator associated with said selecting switches, auxiliary connective means associated with a plurality of operators positions, automatic distributing switches, and means whereby a desired percentage of the telephone trafiic of a group is associated with the auxiliary connective means through the selecting switches and the distributing switches, the. connective means directly associated with the selecting switches being used for trafiic in excess of the desired percentage.

5. In a telephone system, subscribers lines divided. into groups, a plurality of selectingswitches for each group, trunk lines, a plurality of connective means each being individual to one of said trunk lines associated with said selecting switches, auxiliary connective means associated with a plurality of said trunk lines, automatic distributing switches, and means whereby a desired percentage of the telephone trafiic originating in a group is associated with the auxiliary connective means through the select ng switches and the distributing switches, the connective means directly associated with the selecting switches being used for traffic in excess of the desired percentage.

6. In a telephone system, the combination with subscribers lines divided into groups, a plurality of selecting switches associated with the lines of eachgroup, trunk lines extendingfrom a plurality of said switches, connective means directly associated with said trunk lines, other trunk lines extending to other of said switches terminating in distributing switches, auxiliary connective means, said distributing switches being associated with a plurality of said auxiliary connective means, and means preventing the extension of the line circuit through the distributing switch to auxiliary connective means when a line of particular group has been extended from a selecting switch to a connective means in said group,

7. In a telephone system, subscribers lines divided into groups, .a plurality of selecting switches for each group, connective means individual to anoperator, auxiliary connective means associated with a plurality of operators positions, automatic distributing switches, and means whereby a desired percentage of the contacts of the selecting switches-are associated with the auxiliary connective means through the distributing switches, the remainder of the contacts of said switches being directly connected from the selecting switches to the connective means.

In Witness whereof, I hereunto subscribe my name this 28th day of September A; 1)., 1915.

HENRY P. CLAUSEN.

Disclaimer in Letters atent No.1 ,1 92,1 65.

DISCLAIMER.

l,l92,165.--'Henry P. Olausen, Mount Vernon, N. Y. CALL-DISTRIBUTING b'rs'i'mi. Patent dated July 25, 1916. Disclaimer filed June 26, 1917, by the patmiterr, with the consent of the assignee, by mesne assignments, Western Electric (our pony, Incorporated. Enters this disclaimer To claim 7 of said Letters Patent, which is in the following words, to wit: 1. In a telephone system, subscriber's lines divided into groups, a plurality of si-lccting switches for each group, connective means individual to an operator,

auxiliary connective means associated with a plurality of operators positions, automatic distributing switches, and means whereby a desired percentage of the contacts of the selecting switches are associated with the auxiliary connective means through the distributing switches, the remainder of the contacts of said switches being directly connected from the selecting switches to the connective means.

[Ofic'ial Gazette July 17. 1 17.] 

